An article in the IBM Technical Disclosure Bulletin, vol 27, no 10A, March 1985, pp 5496, entitled "Display named objects within a document" teaches a real-time multiple data editor which provides for the integration of all data on a single page in a dynamic editable form. The page may contain both text and non-text object sets such as images, graphics, tables, annotations and handwriting. The user may manipulate these object sets on a page. Each object set is assigned a user-specified name and can be recalled at anytime.
The Multiple Icon Viewing Design Tool (MIDVT) is described in an article of the same name in the IBM Technical Disclosure Bulletin, vol 33, no 10B, March 1991, pp 477-478. It is designed to work with the Microsoft Icon Editor and allows users to i) select and simultaneously display a number of icons on a single screen, ii) arrange and move the icon images anywhere within the screen, iii) present the icons with or without their title, iv) change, modify or eliminate their title, v) adjust the background color of the window on which the icon is displayed and vi) expand the size of the icon.
In the article "Homogeneous Presentation Graphics and Bit Image Integration" in the IBM Technical Disclosure Bulletin, vol 31, no 10, March 1989, pp 345-346, a system for integrating graphics objects and bit images is disclosed. This is achieved by defining an empty or null segment in order to reserve a position for the bit image.
European Patent Application EP-A-0 243 228 (PUBLIGRAFA) discloses a system for the creation of images for publicity documents. The system incorporates a video image reader and a graphic console with keyboard, graphic tablet and a monitor to receive, combine and modify image signals and colors. A computer is used to combine the video and vectorial image signals and creates one picture or a series of pictures simulating a product wrapper.
European Patent Application EP-A-0 352 012 (IBM) discloses a system for displaying graphics images on a display device. The system comprises a memory for storing graphics images represented by a plurality of picture elements. The memory is divided into a plurality of memory buffers and the graphics images can be either stored in a plurality of memory buffers or in successive positions in one of the memory buffers. Image mixing means combine the required picture elements for display.
Similarly U.S. patent U.S. Pat. No. 4,392,130 (ASEA) teaches a method for presenting graphical information in the form of an image in which the image is assembled from a plurality of symbols defined in advance.
An automatic icon generation system is described in the European Patent Application EP-A-0 427 264 (FUJITSU). The system comprises an icon pattern memory for memorizing, as icon patterns, a plurality of graphic elements, an icon synthesizer for generating the icon from the icon patterns, an icon utilization controller and a display controller for displaying the icons.
A number of commercial products are on the market which allow a user to create his or her own graphical displays on a display device such as a VDU terminal. Two of the best known are incorporated into the IBM Presentation Manager and the Microsoft Windows. Microsoft Windows provides a Paintbrush facility which enables the user either to produce a graphical display freehand or to combine pre-defined graphical elements, such as a square, circle, rectangle etc. in order to produce a new image. The image can be colored, enlarged or altered using the provided tools. The image can be saved for later use. Full details of the operation of the Paintbrush window are given in Chapter 8, pp 257-313 of the Microsoft Windows User's guide for the Windows Graphical Environment, Version 3.0, published by Microsoft Corporation, 1990.
General reference to object-oriented programming techniques can be found in Bertrand Meyer, "Object-oriented software construction", Prentice-Hall, London, 1988.
All of the above cited prior art has the disadvantage that for every new application that a developer writes, the graphic display has to be developed from first principles. That is to say, the applications developer has to develop new display techniques out of very simple graphic fragments. The display techniques form part of the applications program and are permanently stored with it.
In addition, displaying complicated graphical objects and allowing users to directly manipulate the interface requires substantial extra programming, especially if the graphic objects may be networked together.
As graphic displays become more complicated, it is necessary to display more and more items on the screen. This can lead to performance problems when drawing the screens and also results in a lack of clarity of the display.